Nuclear reactor fuel assembly (alternatives)

FIELD: nuclear power engineering; fuel assemblies for pressurized-water reactors.

SUBSTANCE: proposed fuel assembly manufactured using prior-art technology and characterized in enhanced in-service bending stiffness has fuel element bundle, spacer grids disposed through height of fuel assembly, top and bottom nozzles joined together by means of added-stiffness elements connected to spacer grids and bottom nozzle. Added-stiffness elements are made in the form of tubes or cylindrical rods and substitute at least one fuel element in other-than-peripheral line of fuel element bundle. As an alternative, fuel element may have added-stiffness elements made in the form of tubes or cylindrical rods substituting one of fuel elements on each edge of peripheral line of fuel element bundle. There is still another alternative in which added-stiffness elements substitute central fuel element on each other-than-adjacent edge of fuel element bundle. Added-stiffness elements may be joined with top nozzle for longitudinal displacement.

EFFECT: enhanced stability of thermomechanical behavior of reactor core in promising cycles, facilitated transport and in-process handling.

4 cl, 7 dwg

 

The invention relates to nuclear energy, and more particularly to fuel assemblies for nuclear reactors with water under pressure.

Prior art

Known fuel Assembly [RF Patent №2093906, CL G 21 3/30, 1998], which contains a hexagonal bundle of fuel elements placed along the height of the Assembly spacer grids, head and tail of the parts connected support elements. The supporting elements mounted on the height from the tail to the top spacer grid and have the form stamped angular plates of zirconium alloy, and are welded to the spacer bars and screws with a tail part. The disadvantage of this design is the complexity of manufacturing parts and welding them to the spacer grids and the possibility of delenatii corners as the reactor, and carrying out transport-technological operations.

Known fuel Assembly [U.S. Patent No. 4285771, CL G 21 3/30, 1981], which contains a hexagonal bundle of fuel elements placed along the height of the Assembly spacer grids, head and tail of the parts connected support elements placed in the corners of the Assembly instead of the portion of the peripheral fuel elements. The disadvantage of this design is that HC is licena the intensity and complexity of manufacturing, as well as inefficient use (with the exception of the energy production process) space occupied by pillars, in the corners of the Assembly.

The closest analogue on essential features of the proposed invention is a fuel Assembly [U.S. Patent No. 4285771, CL G 21 3/30,1981], and chosen for the prototype.

Disclosure of inventions

The aim of the invention is to increase the reliability of fuel assemblies and nuclear safety of the reactor.

The objective of the invention is to increase long-term preservation of the Flexural rigidity of the fuel Assembly in the core.

The technical result is stable thermomechanical behavior of the active zone during operation, the improvement of conditions for transport-technological operations for the transshipment of fuel assemblies.

This technical result is achieved by the fact that in the fuel Assembly of a nuclear reactor containing the bundle of fuel elements (1), installed along the height of the Assembly spacer grids (2), head (3) and a shank (4), United support elements (5), the additional stiffening elements (6)connected to the spacer bars (2) and a shank (4), what is new is that the additional stiffening elements (6) are designed as t the UB or cylindrical rods and replace at least one fuel element (1) in neprimerenog row bundle of fuel elements (1).

This technical result is achieved by the fact that in the fuel Assembly of a nuclear reactor containing the bundle of fuel elements (1), installed along the height of the Assembly spacer grids (2), head (3) and a shank (4), United support elements (5), the additional stiffening elements (6)connected to the spacer bars (2) and a shank (4), what is new is that the additional stiffening elements (6) are made in the form of tubes or cylindrical rods and replace one of the fuel elements (1) each face of the peripheral some bundle of fuel elements (1).

This technical result is achieved by the fact that in the fuel Assembly of a nuclear reactor containing the bundle of fuel elements (1), installed along the height of the Assembly spacer grids (2), head (3) and a shank (4), United support elements (5), the additional stiffening elements (6)connected to the spacer bars (2) and a shank (4), what is new is that the additional stiffening elements (6) replace the Central fuel element (1) each non-contiguous faces of the bundle of fuel elements (1).

When this additional stiffening elements (6) can be connected with the cylinder (3) with the possibility of longitudinal movement, in the example with the aid of guide elements (7).

This design provides increased and long-term preservation of the Flexural rigidity of the fuel Assembly in the core when operating in promising fuel cycles with increasing burnup and time of exposure. This design will also provide for the improvement of conditions for transport-technological operations.

Brief description of drawings

The invention is illustrated by drawings, which presents

figure 1 - fuel Assembly with additional stiffening elements in the bundle of fuel elements;

figure 2 - cross section of fuel Assembly with additional stiffening elements in the bundle of fuel elements;

figure 3 is a fragment of a fuel Assembly with elements additional rigidity and interact with the guide head of the fuel Assembly;

4 is a cross section of fuel Assembly with additional stiffening elements mounted on the axis of symmetry of the non-contiguous faces of the bundle of fuel elements;

5 is a cross section of fuel Assembly with additional stiffening elements arranged offset relative to the axis of symmetry of each face of the bundle of fuel elements;

6 is a vertical section of a fragment of a fuel Assembly in which the guide elements are provided with stops, ogran is to provide vertical movement of the guide elements and the additional stiffness relative to each other;

Fig.7 is a vertical section of a fragment of a fuel Assembly in which the elements of the additional stiffness provided with stops limiting vertical movement of the guide elements and the additional stiffness relative to each other.

Embodiments of the inventions

A fuel Assembly of a nuclear reactor containing the bundle of fuel elements (1), installed along the height of the Assembly spacer grids (2), head (3) and a shank (4), United support elements (5), for example, the guide channels or case, the additional stiffening elements (6)connected to the spacer bars (2) and a shank (4). The additional stiffening elements (6) are made in the form of tubes or cylindrical rods and replace at least one fuel element (1) in neprimerenog row bundle of fuel elements (1).

According to the variant of the additional stiffening elements (6) are made in the form of tubes or cylindrical rods and replace one of the fuel elements (1) each face of the peripheral number of the bundle of fuel elements (1).

Alternatively, the additional stiffening elements (6) replace the Central fuel element (1) each non-contiguous faces of the bundle of fuel elements (1).

For option elements more the positive stiffness (6) can be connected with the cylinder (3) with the possibility of longitudinal movement, for example with the aid of guide elements (7).

The proposed fuel Assembly operates as follows.

When the reactor fuel Assembly is loaded by forces acting on the cylinder (3). In addition, the spacer grid (2) affects the force from thermo-mechanical expansion of the bundle of fuel elements (1). The additional stiffening elements (6)installed in a bundle of fuel elements (1)connected to the shank (4) and spacer bars (2) and interfere together with the support elements (5) deformation of the fuel Assembly, and delenatii grid spacers (2). The additional stiffening elements (6) when installed in a peripheral row can act as guides along which slide the spacer grid (2) adjacent fuel assemblies during installation - removing the fuel Assembly in the reactor. Thereby improve conditions for transport-technological operations.

A proposed decision on essential features of a fuel Assembly of a nuclear reactor has a novelty in comparison with the prototype.

Implementation of the proposed solution are saving Flexural rigidity of the fuel assemblies during operation in promising fuel cycles with increased time exposed the deposits, the improvement of conditions for transport-technological operations.

Economic efficiency of application of the present invention is defined as follows:

- less forming of the active zone that allows operation of the active zone consisting of fuel assemblies of the proposed design in promising fuel cycles with increased efficiency in the use of nuclear fuel;

- improvement of conditions for transport-technological operations, reducing timing of congestion and reduction of the doses.

Industrial applicability

The most appropriate of the proposed solution to use for use on pressurized-water nuclear power reactors.

1. A fuel Assembly of a nuclear reactor containing the bundle of fuel elements (1), installed along the height of the Assembly spacer grids (2), head (3) and a shank (4), United support elements (5), the additional stiffening elements (6)connected to the spacer bars (2) and a shank (4), characterized in that the additional stiffening elements (6) are made in the form of tubes or cylindrical rods and replace at least one fuel element (1) in neprimerenog row bundle of fuel elements (1).

2. Teplovi the pillar Assembly of a nuclear reactor according to claim 1, characterized in that the additional stiffening elements (6) contain the connection to the cylinder (3) with the possibility of longitudinal movement.

3. A fuel Assembly of a nuclear reactor containing the bundle of fuel elements (1), installed along the height of the Assembly spacer grids (2), head (3) and a shank (4), United support elements (5), the additional stiffening elements (6)connected to the spacer bars (2) and a shank (4), characterized in that the additional stiffening elements (6) are made in the form of tubes or cylindrical rods, and replace one of the fuel elements (1) each face of the peripheral number of the bundle of fuel elements (1).

4. A fuel Assembly of a nuclear reactor according to claim 3, characterized in that the additional stiffening elements (6) contain the connection to the cylinder (3) with the possibility of longitudinal movement.

5. A fuel Assembly of a nuclear reactor containing the bundle of fuel elements (1), installed along the height of the Assembly spacer grids (2), head (3) and a shank (4), United support elements (5), the additional stiffening elements (6)connected to the spacer bars (2) and a shank (4), characterized in that the additional stiffening elements (6) replace Central those who lowdelay element (1) each non-contiguous faces of the bundle of fuel elements (1).

6. A fuel Assembly of a nuclear reactor according to claim 5, characterized in that the additional stiffening elements (6) contain the connection to the cylinder (3) with the possibility of longitudinal movement.



 

Same patents:

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The invention relates to fuel assemblies used for dual functions: energy production and regulation of the neutron flux in water-cooled nuclear power reactors, especially in nuclear reactors VVER-440

The invention relates to atomic energy and can be used, in particular, in the construction of fuel assemblies (FA) active zones of nuclear power reactor thermal power from 1150 to 1700 MW, especially for reactors VVER-440

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A fuel assembly // 2220464
The invention relates to energy and can be used in devices for heating water, for example, in nuclear power plants

The invention relates to active zones for water-cooled nuclear reactors on thermal neutrons

FIELD: nuclear power engineering; fuel assemblies for pressurized-water reactors.

SUBSTANCE: proposed fuel assembly manufactured using prior-art technology and characterized in enhanced in-service bending stiffness has fuel element bundle, spacer grids disposed through height of fuel assembly, top and bottom nozzles joined together by means of added-stiffness elements connected to spacer grids and bottom nozzle. Added-stiffness elements are made in the form of tubes or cylindrical rods and substitute at least one fuel element in other-than-peripheral line of fuel element bundle. As an alternative, fuel element may have added-stiffness elements made in the form of tubes or cylindrical rods substituting one of fuel elements on each edge of peripheral line of fuel element bundle. There is still another alternative in which added-stiffness elements substitute central fuel element on each other-than-adjacent edge of fuel element bundle. Added-stiffness elements may be joined with top nozzle for longitudinal displacement.

EFFECT: enhanced stability of thermomechanical behavior of reactor core in promising cycles, facilitated transport and in-process handling.

4 cl, 7 dwg

FIELD: nuclear power engineering; fuel assembly manufacture.

SUBSTANCE: proposed fuel assembly has hexahedral spacer grid with coolant passage holes made in the form of equilateral triangles with rounded-off angles symmetrically disposed relative to holes for bottom plugs of fuel elements or tubular channels in the amount of six ones around each of them, their rounded-off angles being directed toward them; it also has similarly designed round holes for coolant passage.

EFFECT: enhanced flow section of holes for coolant passage through bottom support grid at same desired stiffness; reduced labor consumption and metal input.

2 cl, 7 dwg

FIELD: nuclear power engineering.

SUBSTANCE: proposed fuel assembly designed for use in water-moderated water-cooled reactors, primarily those of VVER-1000 type, is characterized in that its uranium dioxide mass in bundle, outer and inner diameters of fuel element cladding are 436.24 to 561.18 kg, 7.00 · 10-3 to 7.50 · 10-3 m, and 5.94 · 10-3 to 6.36 · 10-3 m, respectively, for bundle of 468 to 510 fuel elements, or uranium dioxide mass in bundle, outer and inner diameters of fuel element cladding are 451.37 to 582.17 kg, 7.60 · 10-3 to 8.30 · 10-3 m, and 6.45 · 10-3 to 7.04 · 10-3 m, respectively, for bundle of 390 to 432 fuel elements, or uranium dioxide mass in bundle, outer and inner diameters of fuel element cladding are 442.22 to 544.12 kg, 8.30 · 10-3 to 8.79 · 10-3 m, and 7.04 · 10-3 to 7.46 · 10-3 m, respectively, for bundle of 331 to 367 fuel elements, water-uranium ratio of subchannel being chosen between 1.27 and 1.83.

EFFECT: reduced linear heat loads and fuel element depressurization probability; enlarged reactor power control range, improved fuel utilization.

4 cl, 11 dwg

FIELD: nuclear power engineering.

SUBSTANCE: proposed fuel assembly designed for use in water-moderated water-cooled reactors, primarily those of VVER-1000 type, is characterized in that its uranium dioxide mass in bundle, outer and inner diameters of fuel element cladding are 436.24 to 561.18 kg, 7.00 · 10-3 to 7.50 · 10-3 m, and 5.94 · 10-3 to 6.36 · 10-3 m, respectively, for bundle of 468 to 510 fuel elements, or uranium dioxide mass in bundle, outer and inner diameters of fuel element cladding are 451.37 to 582.17 kg, 7.60 · 10-3 to 8.30 · 10-3 m, and 6.45 · 10-3 to 7.04 · 10-3 m, respectively, for bundle of 390 to 432 fuel elements, or uranium dioxide mass in bundle, outer and inner diameters of fuel element cladding are 442.22 to 544.12 kg, 8.30 · 10-3 to 8.79 · 10-3 m, and 7.04 · 10-3 to 7.46 · 10-3 m, respectively, for bundle of 331 to 367 fuel elements, water-uranium ratio of subchannel being chosen between 1.27 and 1.83.

EFFECT: reduced linear heat loads and fuel element depressurization probability; enlarged reactor power control range, improved fuel utilization.

4 cl, 11 dwg

FIELD: nuclear power engineering.

SUBSTANCE: members used for fastening fuel element in hole of bottom end spacer grid are made in the form of shortened plug that has coaxial blind hole on its butt-end formed by annular walls expanded (burnished) in hole of larger diameter within bottom end spacer grid.

EFFECT: enhanced reliability of fuel assembly, reduced manufacturing cost and structural material input.

1 cl, 3 dwg

FIELD: nuclear power engineering; fuel assemblies for pressurized-water reactors.

SUBSTANCE: proposed fuel assembly has its guide channels passing for relative movement through spacer grids and secured on fuel bundle by means of interference fit between flexible subchannels and fuel elements, stops being installed on at least one of guide channels above spacer grids. Axial clearances provided between stops and spacer grids are chosen to make it possible for spacer grids to come in contact with stops during radiation elongation when reduction in interference fit between relaxing flexible subchannels and fuel elements, whose diameter decreases due to creepage and radiation, provides for simultaneous slipping of fuel elements through spacer grids.

EFFECT: enhanced reliability of fuel assemblies and safety of nuclear reactor.

1 cl, 3 dwg

FIELD: nuclear power engineering.

SUBSTANCE: supporting ribs of fuel assembly bottom nozzle are droplet-shaped in cross-section and are made in the form of two coaxially disposed rings secured to bottom nozzle so that they are abutting against bottom end of lower spacer grid.

EFFECT: enhanced operating reliability and improved hydrodynamic characteristics of fuel assembly.

1 cl, 4 dwg

FIELD: nuclear power engineering.

SUBSTANCE: the invention may be used in nuclear reactors, in particular in the high-power channel nuclear reactors. The proposed assembly of these reactors is a framework with fuel elements, located in it. The framework has a central tube with the end grates and multi-tier system of spacers, fixed on the tube. This system is fabricated in the form of bent closed ships, skirting the fuel elements. The ships have the spacing bosses and are fastened between themselves. Besides, the fuel elements of internal and external rows contact with the ships, skirting them, in the places more than two. The external and internal rims, fastened with the ships, skirting the fuel elements, are the part of the multi-tier system of spacers. The ships and rims may be fastened between themselves with a shelf and may be fabricated from one sheet.

EFFECT: increased reliability of the fuel assemblies.

12 cl 28 dwg

FIELD: nuclear power engineering.

SUBSTANCE: the invention may be used in nuclear reactors, in particular in the high-power channel nuclear reactors. The proposed assembly of these reactors is a framework with fuel elements, located in it. The framework has a central tube with the end grates and multi-tier system of spacers, fixed on the tube. This system is fabricated in the form of bent closed ships, skirting the fuel elements. The ships have the spacing bosses and are fastened between themselves. Besides, the fuel elements of internal and external rows contact with the ships, skirting them, in the places more than two. The external and internal rims, fastened with the ships, skirting the fuel elements, are the part of the multi-tier system of spacers. The ships and rims may be fastened between themselves with a shelf and may be fabricated from one sheet.

EFFECT: increased reliability of the fuel assemblies.

12 cl 28 dwg

FIELD: nuclear power engineering; production of heat-generating elements and heat-generating assemblies for research reactors.

SUBSTANCE: the invention is pertaining to the field of nuclear power engineering, in particular, to production of heat-generating elements (further - fuel elements) and the heat-generating assemblies (further - fuel elements assemblies) for research reactors using a low (less than 20 %) enriched nuclear material. The technical result of the invention is enhancement of production capabilities for upgrading the existing research reactors, the fissile regions of which differ in dimensions and forms, using the universal rod-shaped fuel element and the based on it fuel elements assembly. The fuel element is made in the form of a tubular sealed on its end faces by plugs shell made out of an aluminum alloy of 0.30 up to 0.45 mm thick with four distancing screw-type ribs on the outer surface. The diameter of a circumscribed circle of a fuel element cross section makes from 4.0 - 8.0 mm. Each rib protrudes above the shell from 0.4 up to 1,0 mm in height and is placed in the cross section plane at an angle of 90° to the neighboring rib and twisted in spiral with a step from 100 up to 400 mm, predominantly from 300 up to 340 m. Inside the shell there is a fuel core made out of a dispersive composition of uranium-containing particles and an aluminum alloy, in which a volumetric content of uranium-containing particles makes up to 45 %, the uranium-containing particles dimension makes from 63 up to 315 microns, and the shell and the core have a diffusion cohesion among themselves, formed at the fuel elements manufacture by the method of a joint extrusion through a forming array of a composite cylindrical blank consisting of the fuel element core, the plugs and the shell. On the basis of the aforesaid fuel element the versions of the heat-generating assemblies are developed for research reactors of different types with various geometrical forms of the fissile regions.

EFFECT: the invention ensures enhancement of production capabilities to upgrade the existing research reactors with different dimensions and forms of their fissile regions with the help of the universal rod-shaped fuel element and the based on it fuel elements assembly.

9 cl, 6 dwg

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